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Real-time Precise Point Positioning And Its Application In Atmosphere Sensing

Posted on:2014-04-15Degree:MasterType:Thesis
Country:ChinaCandidate:M WangFull Text:PDF
GTID:2250330401476851Subject:Geodesy and Survey Engineering
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During recent years, precise point positioning (PPP) technique has evolved towards a set oftheory and methodology offering Internet-based high accuracy real-time positioning service in widearea. Under this technology development background, this thesis elaborates the technique principleand implement details of real-time precise point positioning. The real-time precise point positioningsoftware platform is developed and application results of current real-time orbit and clock productare assessed. In addition, the real-time precise point positioning technique is applied to nearreal-time precipitable water vapor (PWV) inversion and vertical total electron content (VTEC)calculation based on undifferenced observable. The main works and conclusions of this thesis canbe summarized as below:1. Applying the theory of real-time precise point positioning, the experiment softwareplatform named as Positioning Artisan is developed. The experiment results indicate that thepositioning estimation accuracy of Positioning Artisan is comparable to mainstream commercialsoftware. Except for positioning estimation function, the undifferenced ambiguity fixing based onCNES (Center National d’Etudes Spatiales) integer clock, PWV inversion and ionosphere VTECcalculation is realized within this platform.2. The daily estimates using CNES real-time orbits and clocks are analyzed, whichdemonstrates their comparable accuracy to those derived with IGS post-time product. Thecorresponding results show that the undifferenced ambiguity using CNES integer clock couldevidently improve the real-time PPP solution convergence speed.3. The real-time PWV inversion data processing scenario is researched. Corresponding resultsindicate that the accuracy of CNES real-time orbits and clocks could meet the need of real-timePWV inversion. The method to obtain ground meteorology data with VMF1(Vienna MappingFunction1) gridded data is come up. Comparing with PWV inversion results that relies on directmeteorological measurements, the VMF1gridded data could be a reliable ground meteorologyinformation source.4. The real-time PWV inversion method without direct meteorology observables is discussed.The experiment results suggest that because of relatively low sensibility of PWV inversion to errorsof orbit and clock product, both GPT model and VMF1gridded data could be reliable supplementsource of meteorology information. The meteorology observation independent PWV inversionmethod come up by this thesis could improve the flexibility of meteorology observation deploymentand further exert the application potential of current GPS observation station built for geodesy studypurpose. 5. The phase leveling pseudorange ionosphere observable conventionally applied in VTECcalculation is noisy and vulnerable to systematic error of pseudorange. To avoid this problem, a nearreal-time VTEC estimation method using ionosphere observable combined with carrier-phase iscome up. The short-and zero-baseline experiment results under high ionospheric activitydemonstrates this method could exclude the multipath delay and inter-frequency bias ofpseudorange to yield more accurate VTEC estimate, moreover, the result timeliness is improved byusing broadcast ephemeris.
Keywords/Search Tags:real-time precise point positioning, extended Kalman filter (EKF), undifferencedambiguity fixing, integer clock, precipitable water vapor, VMF1gridded data, GPT model, verticaltotal electron content (VTEC)
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